The .beta.-lactam ring ##STR4## has been known since the late nineteenth century. Since then, myriad penicillins, cephalosporins, and monobactams have been discovered (see the discussion of prior art in U.S. Pat. Nos. 4,775,670 and 4,533,670, issued Oct. 4, 1988 and Aug. 6, 1985, respectively). One recently discovered antibiotic is aztreonam ("Azactam".RTM.), which has the structure ##STR5## (see U.S. Pat. No. 4,775,670). Another recently discovered antibiotic is tigemonam, which has the structure ##STR6## (see U.S Pat. No. 4,533,660).
Still other beta-lactam antibiotics are ceftazidime, which has the structure ##STR7## (see inter alia U.S. Pat. Nos. 4,258,041 and 4,600,772); cefixime, which has the structure ##STR8## (see inter alia U.S. Pat. No. 4,409,214); and carumonam sodium, which has the structure ##STR9## (see inter alia European patent application no. 93,376 A2).
Such antibacterial agents possess aminothiazolyl(iminooxyacetic acid)acetic acid sidechains. Many such compounds are described in the literature; see, for example, United Kingdom patent application no. 2,071,650 (published Sep. 23, 1981). The art would benefit, therefore, from processes that would efficiently produce beta-lactams having aminothiazolyl(iminooxyacetic acid)acetic acid sidechains.